The key to any high precision machining operation using a single or multi-fluted rotary tool is to achieve the lowest radial runout and axial deviation from the center line that is possible. Current spindle designs use a tapered device, a collet device or a straight device with a very close fit in an attempt to achieve the desired accuracy. Each of these arrangements requires high precision parts relative to their tapers, clearances etc. These spindle designs retain the tool by: 1) a collet; 2) a drawbar which may be either threaded or of an automatic tool changer type; or, 3) threads and jam nuts. These designs have many pieces which result in the stacking up of tolerances/inaccuracies, there are problems with drawbar balancing, and there are high costs. These designs produce many points in the system with a potential for producing cumulative radial runout and axial deviation. They are, for example, the location of the spindle, the location of the tool holding device in the spindle and the location of the tool in the tool holding device.
Commonly assigned U.S. Pat. No. 5,141,370 addresses the stacking up of tolerances by providing a direct interface between a spindle and a cutting tool. While this improved the accuracy by the elimination of parts, the cantilevered supporting of the tool can introduce errors at the remote, cutting end of the tool.